While it is known for mobile terminals to have the capacity to record audio, the generally small size of typical mobile devices presents challenges for such capture, particularly capture of multichannel audio. Where such a mobile user device has multiple microphones, one reason that it is difficult to achieve a subjectively good sonic image is that all microphones are necessarily spaced apart by a distance no larger than the size of the device itself, with typically spacing in the range of about 5-15 cm. For a subjectively good and spacious-sounding audio recording, it is generally preferred that at least some of the microphones be spaced apart (in more than one direction) by up to several meters. This is especially true if the microphones are omnidirectional rather than directional. If all microphones are spaced close together as they must be when on a single mobile terminal, the end result usually suffers from one or more of the following artifacts:                Poor envelopment and spaciousness. The result of this is that the recording does not sound like the acoustic space it was recorded in, and to restore some of this impression, additional processing must be employed.        Lower signal-to-noise ratio. This is because more extensive processing of the microphone signals may be needed, for example, to artificially generate directivity in spite of the fact that the actual microphones are omnidirectional.        Possible artifacts from steering algorithms. Steering algorithms may have to be employed in order to achieve a reasonable separation between channels. Artifacts may arise, for example, when multiple sound sources are spread around in several directions and sounding at the same time.        Low flexibility. This arises from the fixed positioning of the microphones; algorithms can be employed to alter the directional patterns, delays etc., but only within reasonable limits.        Further processing artifacts for example from channel de-correlation during digital signal processing.        Heavier processor load, due to the additional processing needed.        
For proper surround sound capture the mobile user device would need to be equipped with at minimum three distinct microphones. Related teachings concerning multi-channel audio may be seen at commonly assigned U.S. patent application Ser. No. 12/291,457 by Juha P. Ojanpera, filed on Nov. 10, 2008 and entitled Apparatus and Method for Generating a Multichannel Signal.
Regarding capture of 3-dimensional video, at least some of the same limitations apply. Normally, one would use two cameras to capture stereo video, one camera for each eye. But the optimum distance between cameras (termed the stereo base) is dependent on the distances to the nearest and farthest points of the scene to be captured, and also on the captured angle (wideangle, normal, or short telephoto). Also the stereo base depends on the desired apparent depth of the resulting 3D video. The end result for stereo video is that typically the best stereo base is larger than can be accommodated by the maximum size of a typical mobile device. From an economic rather than a technical perspective, installing multiple cameras in a mobile user device adds to the cost and to its bulk.